The present invention is directed to a hose-shaped bag formed of a composite foil including a metal foil and at least one outer plastic foil in contact with the outer surface of the metal foil. Hose-shaped bags of this type are used mainly for storing curable or hardenable masses, in particular multi-component masses, such as mortar masses and the like.
After filling with a component of a mass, the hose-shaped a bag is closed, for instance, by welding or by sealing its ends with sealing clips formed of metal.
In the filled state, the hose-shaped bags are inserted in dispensing tools where the mass is squeezed or pressed out to process it, and the hose-shaped bags are emptied by a compressing and squeezing action on the bags by parts of the tool. To commence the dispensing operation, it is necessary to open the hose-shaped bags.
Various ways are known for opening the hose-shaped bags. It is known to cut the hose-shaped bags open by a special cutting device before the bag is introduced into a dispensing tool.
Such an opening procedure has the disadvantage that the mass can escape from the hose-shaped bag immediately after it is cut open resulting in fouling or contamination of the dispensing tool as well as its surroundings.
For this reason, it is a widely accepted procedure to equip the dispensing tool with an opening member, such as a puncture pin or a puncture edge. The cooperation of such an opening member with a hose-shaped bag inserted into the dispensing tool is intended to assure that the bag is opened while in the tool, which, with a suitable design, can take place after the tool has been closed.
In actual practice it has been found that the above-mentioned preferred method of opening hose-shaped bags involves certain difficulties and does not always lead to the desired result. This occurs because composite foils, used as the material in hose-shaped bags, have a relatively high mechanical strength.
As an example, composite foils are made up of one or more plastic foils as well as one or, if necessary, several metal foils. This layered construction of composite foils is arranged for protection against chemical influences with a plastic foil layer forming the outside surface of the bag.
Preferably, polyurethane, as the plastic material, and aluminum, as the metal material, are used in forming composite foils. The high mechanical strength or resistance required for composite foils both for storage and transport has disadvantages in opening the hose-shaped bag. Often, the opening members in the dispensing tool are insufficient to overcome the mechanical strength of the composite foil and fail to open the hose-shaped bag at the desired time and location.